Fig 1: The fundamentals of R factor

Volume: 07 Issue: 10 | Oct 2020 www.irjet.net p-ISSN: 2395-0072

Ductility Factor (Rμ):

It is the ratio of ultimate or maximum base shear to the base shear corresponding to the yield of the structure. It representsthe nonlinear response ofthe structure.

Rμ = 1.0 for zero-period structures Rμ = 2μ – 1 for short-period structure Rμ = μ for long period structure Rμ = 1+ (μ-1) T/0.70 (0.70 s < T < 0.3) Where, ‘μ’ is given by μ = Δu / Δy, where Δu is ultimate deformation and Δy is yield deformation.

Damping factor (Rξ):

It shows the effect of ‘added’ viscous damping and is primarily applicable for structures provided with supplemental energy dissipating devices. Without such devices, the damping factor is generally assign a value equal to 1.0 and is exclude from the explicit components of response reduction factor used in force-based design procedures.

Redundancy Factor (RR):

It is measure of redundancy in a lateral load resisting system. In RC structures, the moment resisting frames, shear walls or their combinations are the most preferred lateral load resisting systems. Sometimes, the central frames are only design for gravity loads and the perimeter frames are design as the lateral load resisting systems. Thus, the redundancy in lateral load resisting systems depends on the structural system adopted. ASCE 7 recommends a redundancy factor RR= 1.0.

Fig -1: The fundamentals of R factor

2. OBJECTIVES

 The main objective of study is to perform performance-based analysis i.e. to obtain performance levels of buildings for the future earthquake and understand its collapse mechanism in case of extensive damage  To study the real behaviors of RC buildings in through non-linear analysis and suggest the circumstance, which affects the response of the structure.

3. SCOPE OF WORK

 Selection of an appropriate structural layout for new as well as an existing R.C.C. building.  Carryout Static Nonlinear Analysis (Pushover

Analysis) for R.C.C. building.  Generate pushover curve (Base Shear-Roof

Displacement) for R.C.C. building.  Obtain Demand curve by converting Response

Spectrum into ADRS (Acceleration Displacement

Response Spectrum) format.  Superposition of Capacity curve and Demand Curve to obtain performance point for a specific level of earthquake.  Evaluation of building performance with reference to performance point.  Understanding the collapse mechanism of different structural members of a R.C.C. building.  Find out the response reduction factor and compare with value given by code

4. PROBLEM STATEMENT

To evaluate the seismic response of Reinforced concrete building, we considered fourdifferent structure located in seismic zone III. The linear dynamic analysis is perform considering Response spectrum method. The nonlinear dynamic analysis carried out using displacement controlled pushover analysis. The details of the material, geometry, configuration as given below.

Table -1: Input Parameters

Specification S1 S2 S 3 S4

No. of stories 22 23 20 23 F to F Height 3 3 4.1 3

Type Residential Office Office Office Internal wall 150 200 150 230 External wall 230 200 230 230

Slab Thk. 150 200 200 225 SIDLon Floor 1.5 1.2 1.5 1.2 SIDL onRoof 2.5 2.5 2.5 3.3

LL on Floor 3 4 4 4

LL on Roof 2 2 2 1.5

Table -2: Seismic details of Structure

Specificati on S1 S2 S 3 S4

FrameType SMRF SMRF SMRF SMRF

Soil Type Medium Medium Medium Medium I 1 1 1 1

R factor 5 5 5 5

Damping 5% 5% 5% 5%

Response IS1893: IS1893: IS1893: IS1893: